Signal to Noise Ratio (SNR) is one of the key statistics in determining operational parameters between devices communicating with one another. Accurate SNR measurements are crucial for determining ultimate data transmission parameters, especially in IEEE 802.16 standard based wireless product development. IEEE 802.16 corresponds to IEEE Std. 802.16-2004 “IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems” and IEEE Std. 802.16e-2005 “IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems.” Fast SNR measurements and calculations are key to improving the speed of the data transmission.
It has been challenging to engineer an accurate and low complexity SNR algorithm. SNR calculations have typically been conducted in the time domain using time expensive square root functions. To determine SNR values, typically a signal is received in a device. Such signal may be represented as: rk, where k=1-255. The SNR value typically is calculated as:
  SNR  =                  X                                  E        -                            X                                                    where,        
      X    =          2      ⁢                          ⁢                        ∑                      k            =            0                    127                ⁢                                  ⁢                              r            k                    ⁢                      r                          k              +              128                        •                                ,
  E  =                    ∑                  k          =          0                255            ⁢                          ⁢                        r          k                ⁢                  r          k          •                      ⁢                  =                  ∑                  k          =          0                255            ⁢                                              r            k                                    2            and |X| is the absolute value of complex data X and calculated as |X|=√{square root over ((real(X))2+(imag(X))2)}{square root over ((real(X))2+(imag(X))2)}. This square root operation is a very time costly operation.
Thus, in order to improve data transmission in wireless devices there exists a need for more efficient, accurate, and noise insensitive techniques to determine SNR value for signals received in wireless communication devices.